Speed changing transmissions for use in power presses and like machines



1959 F. MEYERCORDT.

SPEED CHANGING TRANSMISSIONS F OR USE IN POWER PRESSES AND LIKE MACHINESFiled Feb. 16, 1955 2 Shets-Sheet 1 Nov. 10, 1959 F. MEYERCORDT SPEEDCHANGING TRANSMIS Y SIONS FOR USE IN POWER PRESSES AND LIKE MACHINES 2Sheets-Sheet 2 Filed Feb. 16, 1955 SPEED CHANGING TRANSMISSIONS FOR USEIN POWER PRESSES AND LIKE MACHINES Fritz Meyercordt, Goppingen, Germany,assignor to L. Schuler A.G., Goppingen, Wnrttenrberg, GermanyApplication February 16, 1955, Serial No. 488,640

Claims priority, application Germany March 19, 1954 7 Claims. (Cl.192-4) This invention relates to power presses, and more particularly tospeed changing mechanisms for use in presses and like power-operatedmachines.

It is an object of the present invention to provide means facilitating acompact mechanism of the aforesaid type, which requires a minimum ofspace and is economic and time-saving in operation by imparting to theoperating element or elements of a press a relatively greater speedduring the return strokes than during the forward or power strokes.

It is another object of the present invention to provide means affordinggreatly simplified and highly accurate mechanisms for regulating thespeed of travel of a ram or like element of a power press during boththe power and return strokes, whereby said ram is advanced to itsworking or operative position at a relatively slow rate and is returnedto its starting or inoperative position at a relatively fast rate.

Still another object of the present invention is to provide meanscontributing to novel and improved mechanisms ensuring movement of a ramof a power press or like machine at a relatively greater speed duringits return stroke than during its power stroke, which mechanisms may beused with power presses and like machines equipped with conventionalconstant-speed driving means Without necessitating any changes in theoperational speed of the driving means to effect changes in ram speed.

A further object of the present invention is to provide means conduciveto extremely efiicient speed varying mechanisms for power presses andlike machines, which mechanisms are inexpensive to manufacture and maybeconstructed for use with and for ready adaptation to existing machines,presses, and like power-operated aggregates.

Still a further object of the present invention is to provide meanspresenting highly effective, clutch-operated, speed changing mechanismsand transmissions for use with power presses and like machines, to bedirectly mounted on the frame of the latter so as to constitute aneasily accessible connection between the power drive on the one hand andthe power transmission means for the operating elements on the otherhand.

It is also an object of the present invention to provide means leadingto self-contained and automatic speed changing transmissions for usewith power presses and like machines, whereby operation of saidtransmissions may be easily controlled directly or indirectly by theoperating elements of such presses or machines.

Generally it is known to move the ram or operating element of a powerpress or like machine during its return stroke at a greater speed thanduring its power stroke. For example, it is common practice to retractthe ram of a metal drawing machine at double the speed with which it isadvanced during the drawing operation. The greatest advantage of such amanner of operation is the time saving involved.

in some known constructions, these'higher speeds of atom: O

return stroke movement of the ram are attained by means of aWard-Leonard control, the rpm. of the drive motor of such control beingreduced during the power stroke of the ram and increased during thereturn stroke. Such an arrangement, however, has the disadvantage that,by virtue of the speed changes occurring, no flywheel can be employed asthe power means, so that the drive motor must be powerful enough to beable to sustain the entire load.

It is further known to attain variable ram speeds during an operatingcycle of the load shaft by means of a linkage or lever system. Suchconstructions are, however, extremely complicated and correspondinglyexpensive to install and maintain in working condition.

One of the primary objects of the invention is, therefore, to overcomethe aforesaid disadvantages inherent in the known drives for powerpresses or like machines and to provide means considerably improvingfunction, operation and surveyance of such such presses while stillemploying electrical motor means and a flywheel as drive means.

In accordance with the invention, the advantage is obtained that,despite the variation of operating speeds during any one cycle of thepress, ordinary electric constantspeed motors can be employed inconjunction with a flywheel to actuate the press. No matter how greatthe variation in operating speed, the rotational speeds of the drivemotor and the flywheel remain constant throughout the entire operatingcycle. The energy stored in the flywheelby virtue of the greater speedof the operating element during its return stroke is subsequentlyemployed, after the speed is decreased, for aiding the operation of saidelement during its power stroke.

The invention will be more fully and comprehensively understood from aconsideration of the following detailed description when read inconnection with the accompanying drawings which form part of theapplication, with the understanding, however, that the improvement iscapable of extended application and is not confined to the exact showingof the drawings nor to the precise construction described and,therefore, such changes and modifications may be made therein as do notaffect the spirit of the invention nor exceed the scope thereof asexpressed in the appended claims.

. In the drawings:

Fig. 1 is a schematic front view in elevation ofthe upper portion of apower press or like machine incorporating a speed varying transmissionor mechanism embodying the present invention; and

Fig. 2 is a schematic top plan view of the mechanism of Fig. 1, certainparts being shown in section.

Referring now more particularly to the drawings, an electric drive motor1 is mounted on and suitably affixed to the top of upper portion 18 of apower press frame. A flywheel 2 is driven by motor 1 through V-belts 1',the flywheel being mounted on or otherwise connected to an input shaft 3of the speed changing mechanism 17. Aflixed to shaft '3 at spacedlocations thereon are two gears 4 and 5.

An output shaft 6 is journaled in housing 17 of the speed changingtransmission and extends parallel to input or counter-shaft 3. Gears 7and 8, which, together with gears 4 and 5, constitute the means fortransmitting the motion of shaft 3 to shaft 6, are loosely disposed ondrive shaft 6 so as to be freely rotatable thereon, gear 7 meshing withgear 5, and gear 8 meshing with gear 4.

In the illustrated embodiment of the invention, gears 5 and 7 have thesame diameter and number of teeth, while gear 8 has a considerablygreater diameter than gear 4 and a correspondingly larger number ofteeth. The dimensions of the respective gears are so chosen that gear 8is'dr'iven at'approximately half the rotational speed at which gears 4,5, and 7 are driven.

Disposed on shaft 6 on either side of housing 17 are two disc or plateclutches 9 and 1%. Gear 8 is fixedly connected with the housing ofclutch 9, and gear 7 is fixedly connected with the housing of clutch 16.In each of the two clutch housings there is provided a plurality offixed clutch plates 9' and 1t). Attached to shaft 6, as by keys 11' and12', and disposed within the housings of clutches 9 and 10,respectively, are plate supports 11 and'12 which carry groups of plates9" and 19" corresponding to the plates carried by the housings andprojecting in between the last-mentioned plates.

The clutches are actuated by axial displacement of sleeves 29 and 29which slidably surround shaft 6 and act on levers'30 and 30',respectively, these levers being pivotally supported on housings 9 and10. Displacement of sleeves 29 'and 29' is effected by means ofsuitable, preferably pneumatic pressure devices, which include pneumaticcylinders 13 and 14 disposed adjacent the ends of shaft 6 and connectedto sources of air under pressure through pipes or conduits 13a and 14a,respectively. Shaft 6 is provided with central bores 13 and 14 whichextend therethrough to the housings of clutches 9 and 10, piston rods13" and 14" being slidably arranged in said bores, respectively, andactuated by pistons 13b and 1% located within the cylinders. Thesepiston rods are connected to sleeves 29 and 29' by means of projectionsor like elements extending through transverse slots in the wall of shaft6.

A disc-type brake, generally designated as 15, is provided on driveshaft 6 adjacent one end thereof, the fixed portion of the brake beingmounted on an external support'31 Connectedto the brake housing, as bybeing threadedthereinto, is a pressure cylinder 32 in which a pressurepiston 33 having a small displacement stroke is located. Piston 33 maybe forced by means of compressed'airagainst springs 34, which ordinarilysupply the braking forces, so as to lift the top disc or plate 15 of thebrake from the remaining discs, thereby releasing the 'brake. A brakingaction on the shaft results when the compresed air is removed so as topermit springs 34 to press the top disc of the brake back against theremaining discs. 7

Fixed to shaft 6 by suitable means, such as a key 16, is a drive oroutput gear 16. Gear 16 meshes with an intermediate gear 19 (see Fig. 1)disposed in press frame 18. Gear 19 is fixedly connected to a pinion 20disposed coa-xially therewith and which drives a gear 21 meshing in turnwith a gear 22 of like diameter. Fixedly connected with gears 21 and 22and disposed coaxially therewith, respectively, are two pinions 23 and24. Pinion 23 drives a crank shaft 27 through an intermediate gear 25,and pinion 24 drives a second crank shaft 28 disposed parallel to crankshaft 27 through an intermediate gear 26.

In operation, if the press is in the condition represented by crankshaft position a (see Fig. 1), which position indicates the starting ofthe press, clutch plates 99" are caused'to engage by means of fluidunder pressure fed to pneumatic device 1.3--13 while brake 15 isreleased simultaneously. Output shaft 6 is, therefore, driven by gears 4and "8 at a relatively low rotational speed all through the power strokeof the operating element of the press.

When crank shafts 27 and 28 reach position [1 (see Fig. 1), whichposition indicates the end of the power stroke and the start of thereturn stroke, the pneumatic device 13-13" is automatically deactuatedand pneumatic device 1414" actuated in its place, so that clutch plates9'9f are disengaged and clutch plates 10'10" are brought intoengagement. Thereafter, output shaft'6 is driven through gears and 7 ata relatively high rotational speed adapted for the return stroke of theram or other operating element.

As soon as the crank shafts come back to position a, pressure orpneumatic device 1414" is deactuated and clutch plates 10-10"disengaged. If the machine runs continuously, then the aforementionedprocedure is repeated. If it be desired, however, to carry out a singlecycle operation, or to delay the start of a new power stroke uponcompletion of a preceding return stroke, then the brake 15 is actuatedautomatically to inhibit rotation of shaft 6 and gear 16 jointly withrelease of the clutches. Releasing of the clutches upon deactuation ofthe pressure devices is effected in a known manner by means of returnsprings (not shown) acting on the movable clutch plates or by means of areversal of the pressure applied to the pistons accomplished, forexample, by manipulation of suitable reversing valves (not shown)interposed in the lines between the cylinders and the source ofpressure.

The entire system is preferably so constructed that the time intervalsbetween actuation of the pressure devices, corresponding to the periodsof time required for the crank shafts to move from position a toposition b and vice versa, are adjustable. The principles of the presentinvention may further be so developed and modifi ed as to render themadaptable to implementation in connection with any press or likemachine, whether the latter is driven continuously or with any desirednumber of single, interruptedcycles of operation.

It will also be readily realized that a speed changing mechanism inaccordance with the present invention may be applied to all types ofpower presses, such as stroke of the operating element of the press ormachine at a lesser speed than that of the return stroke.

Having thus described the invention, what is claimed as new and desiredto be secured by Letters Patent, is:

1. A speed changing mechanism for use in connection with an operatingelement of a power press and like machine equipped with a flywheel drivefor said operating element; comprising input shaft means adapted to bedriven unidirectionally by said flywheel drive, output shaft meansdrivingly connectable to said operating element, at least two motiontransmission means operatively connected to said input shaft means anddrivable by the latter at different, predetermined codirectional speeds,clutch means operatively connected to said motion transmission means andoperable to selectively connect said motion transmission means to saidoutput shaft means to thereby enable the latter to be driven atsuccessive, predetermined codirectional speeds commensurate,respectively, with the respective speeds of said motion transmissionmeans, whereby said operating element may be driven through said outputshaft means at one predetermined speed during a first portion of itsoperating cycle and at another predetermined speed during a secondportion of its operating cycle, brake means operatively disposedrelative to said output shaft means and normally engaged with the latterto inhibit motion thereof upon deactuation of said clutch means, andreleasing means operatively connected to said brake means for operatingthe latter to release said output shaft means upon actuation of saidclutch means.

2. A mechanism according to claim 1, said brake means comprising a discbrake including plate-like braking elements and resilient meansoperatively connected to some of said braking elements to normally biasthe latter i'nto braking action with respect to said output shaft means,said releasing means comprising fluid-operated piston and'cylinder meansoperatively connected to said resilient means and operable to counteractthe braking forces engendered by said resilient means upon said brakingelements.

3. A speed changing transmission, comprising a housing, parallel inputand output shafts journaled in said housing for unidirectional rotation,respectively, at least two input gears fixed at spaced locations on saidinput shaft for unidirectional and codirectional rotation therewith, atleast two output gears loosely supported on and concentrically with saidoutput shaft, each of said output gears meshing with a respective one ofsaid input gears, said output gears having different diameters withregard to one another, whereby said output gears are driven withpredetermined unidirectional and codirectional angular speeds differentfrom one another, at least two clutches operatively connected,respectively, to said output gears and operable to selectively connectthe latter to said output shaft to impart to the latter, respectively,said predetermined angular speeds, a brake having a first brakingportion connected to said output shaft and rotatable therewith, a secondbraking portion fixed relative to said output shaft, and meansoperatively connected to one of said braking portions for selectivelyengaging and disengaging the same from the other braking portion.

4. The combination, in a power press and like machine tool having anoperable element performing at least one cyclic operation, ofunidirectionally driven input shaft means, output shaft means, a gearinginterconnecting said input shaft means with said output shaft means,said gearing including respective pairs of meshing gears having a spacetherebetween and being of predetermined speed ratios to move saidoperable element at relatively slow speed during one part of said cyclicoperation and at relatively greater speed during another part of saidcyclic operation, clutch means disposed at either side of said gearingand on said output shaft means, respective operable means carried bysaid output shaft means for actuating and deactuating said clutch means,selectively, and output gear means operatively connected to saidoperable element and carried by said output shaft means in said spacebetween said pairs of respective meshing gears.

5. The combination according to claim 4, including brake means for saidoutput shaft means and mounted 'on the latter adjacent one of saidclutch means to stop said operable means during said cyclic operation.

6. The combination, in a power press and like machine tool having anoperable element performing at least one cyclic operation, ofunidirectionally driven input shaft means, output shaft means, a gearinginterconnecting said input shaft means with said output shaft means,said gearing including respective meshing gears of predetermined speedratios to move said operable element at relatively slow speed during onepart of said cyclic operation and at relatively greater speed duringanother part of said cyclic operation, clutch means disposed at eitherside of said gearing and on said output shaft means, respective operablemeans carried by said output shaft means for actuating and deactuatingsaid clutch means, selectively, output gear means operatively connectedto said operable element, and brake means on said output shaft means tooperate the latter during said cyclic operation for stopping saidoperable element.

7. The combination, in a power press having an operable elementperforming at least one cyclic operation, of a pair of rotatable shafts,a gearing interconnecting said pair of shafts, said gearing includingrespective pairs of meshing gears having a space therebetween and beingof predetermined speed ratios to move said operable element atrelatively slow speed during one part of said cyclic operation and atrelatively greater speed during another part of said cyclic operation,clutch means disposed on one of said pair of shafts, respective operablemeans carried by said one of said shafts for actuating and deactuatingsaid clutch means, selectively, and output gear means operativelyconnected to said operable element and carried by said one shaft in saidspace between said pairs of respective meshing gears.

References Cited in the file of this patent UNITED STATES PATENTS2,304,032 Schmitter Dec. 1, 1942 2,465,942 Von Sundt Mar. 29, 19492,557,896 Soule et a1. June 19, 1951

